2.4.4 Notes about installation (for Linux)
This subsection provides Linux-specific notes about installation when SNMP Agent for Linux systems is installed. For installation notes common to all OSs, see 2.4 Notes about installation.
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Some OS files are changed when an SNMP agent is installed. If snmp 161/udp is not defined in the file /etc/services, it is added to the file /etc/services.
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Confirm that the Linux native agent is installed.
If the Linux native agent is not installed, install it as follows:
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To confirm whether the native agent is installed, execute the following command as a superuser:
#rpm -qa | grep net-snmp
If the results below are shown, the native agent is installed. If the results below are not shown, then the native agent is not installed. If that is the case, install the native agent by using the rpm command.
In RHEL 6, CentOS 6, and Oracle Linux 6:
net-snmp-x.x.x.x
net-snmp-libs-x.x.x-x
net-snmp-utils-x.x.x-x
In RHEL 7, CentOS 7, and Oracle Linux 7:
net-snmp-x.x.x.x
net-snmp-libs-x.x.x-x
net-snmp-utils-x.x.x-x
In SUSE Linux 12:
net-snmp-x.x.x.x
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In RHEL 6, CentOS 6, and Oracle Linux 6, check the OS auto-start files.
Confirm that the OS auto-start files in /etc/rc.d/rc3.d, /etc/rc.d/rc4.d, and /etc/rc.d/rc5.d have symbolic links attached to them from the file /etc/rc.d/init.d/snmpd. Symbolic links are usually attached to the S50snmpd file in the above directories. If no symbolic links exist, configure auto-start setting so that snmpd starts at run levels 2, 3 and 5 when OS starts.
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In RHEL 7, CentOS 7, Oracle Linux 7, SUSE Linux 12, execute the following command to confirm whether snmpd service is enabled.
systemctl is-enabled snmpd.service
If "enabled" is displayed as a result, snmpd service is enabled. If snmpd service is not enabled, execute the following command to enable snmpd service.
systemctl enable snmpd.service
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In RHEL 6, 7, CentOS 6, 7, and Oracle Linux 6, 7, Change the configuration of the native agent.
Under the default setting, the native agent responds to only MIBs for the system group. Change the file /etc/snmp/snmpd.conf as follows, so that all MIB groups are responded to.
<Before change>
view systemview included .1.3.6.1.2.1.1
view systemview included .1.3.6.1.2.1.25.1.1
<After change>
view systemview included .1.3
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Start the SNMP agent.
To start the SNMP agent, reboot the machine or execute the following procedure as a superuser:
In RHEL 6, CentOS 6, and Oracle Linux 6:
/opt/CM2/ESA/bin/snmpstop (#)
/etc/rc.d/init.d/snmpd restart
/opt/CM2/ESA/bin/snmpstart
In RHEL 7, CentOS 7, Oracle Linux 7, and SUSE Linux 12:
/opt/CM2/ESA/bin/snmpstop (#)
systemctl stop snmpd.service
systemctl start snmpd.service
/opt/CM2/ESA/bin/snmpstart
#: If the SNMP agent is running, stop it.
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Define the node in the Linux file /etc/hosts.
The SNMP agent asynchronously sends events that have occurred to the manager by using SNMP trap messages. Each message contains the IP address of the host from which it is sent. Each IP address corresponds with a particular host name.
When Linux is installed, the IP address of the node in the file /etc/hosts might be xxx.0.0.1. The following is an example of how to define a host name (linux01) in the file /etc/hosts:
127.0.0.1 linux01 localhost.localdomain localhost
In the definition of /etc/hosts in the above example, the IP address corresponding to linux01 is 127.0.0.1.
In the /etc/hosts file, specify the local IP address, instead of 127.0.0.1, for the local node.
The following is an example of such a definition in the file /etc/hosts:
127.0.0.1 localhost.localdomain localhost 172.16.49.18 linux01